"TALL PLANT CUTTING HEAD FOR SELF-PROPELLED CHIPPING MACHINES". DESCRIPTION

This invention concerns a head for cutting tall plants, for use in association with self-propelled chipping machines and particularly suitable for use in cutting poplar trees grown on a short two-year cycle.

It is common knowledge that wood chips are needed for the purpose of making chipboard panels and for fuelling thermoelectric power plants. It is also common knowledge that the tree most often used to obtain said wood chips is the poplar.

When it is still young, the poplar is cut and chopped to obtain the required size of chipped wood.

According to the current state of the art, the operator cuts the plant with manual tools and then places it in the chipping machine, from the outlet of which the chopped poplar wood can be collected.

Clearly, this procedure carries certain acknowledged drawbacks. A first of these drawbacks obviously lies in that having to proceed manually with the cutting of the poplar tree and its insertion in the chipping machine means that the processing times are particularly lengthy. Another drawback relating to the known state of the art lies in that the process is particularly tiring for the operator.

Another, not necessarily last drawback relating to the known state of the art consists in that this procedure also proves particularly costly, demanding the presence of numerous operators to speed up the process and obtain an appreciable quantity of product during the working day.

To overcome the above-mentioned drawbacks, there is a known type of head for cutting tall plants that can be associated with a self-propelled chipping machine; said head has a frame complete with means for coupling it to the chipping machine and an associated unit for cutting the plants close to the ground.

This cutting unit consists of a pair of revolving blades with a plurality of lifting devices installed over them, which lift the poplar stem and direct it towards a chipping unit forming part of the self-propelled chipping machine. This solution overcomes the previously-mentioned drawbacks, but has further acknowledged intrinsic weaknesses.

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The first of these weaknesses lies in that this head can be used exclusively with very young plants, having a diameter of the stem no greater than 7-8 cm. This means that, in the particular case of poplar trees, the cutting head can only be used with plants that are no more than one year old. This drawback derives from the fact that, if the stem of the plant being cut is too large in diameter, when it reaches the chipping unit forming part of the self- propelled chipping machine, it is not flexible enough to bend and consequently cannot be chopped properly. To be more precise, most of the times the stem slides diagonally inside the chipping machine, consequently blocking the machine and preventing it from operating smoothly.

A further drawback of the above-described head consists in that it is made with hydraulic transmission systems, which makes it necessary to apply hydraulic pumps to the self-propelled chipping machine in order to drive said transmission systems.

A further drawback, which derives from the above, lies in that said head is particularly costly to manufacture.

Other drawbacks include the fact that the head is rather complex in design, making it also far from easy to service, in addition to the fact that, as mentioned earlier, it cannot be used for cutting poplar trees that are more than one year old.

This last aspect is a particularly important limitation because it is common knowledge that more adult poplar trees, e.g. those approximately two years old, are more suitable for the purpose of manufacturing chipboard panels and for the production of chipped wood for use as fuel in power plants.

In fact, the characteristics of their wood are far more suitable for the production of energy by means of a thermoelectric procedure or for the manufacture of chipboard panels. Moreover, such older poplar trees clearly provide a larger quantity of wood chips than trees that are cut after one year.

The object of the present invention is to overcome all the above-mentioned drawbacks typical of the known state of the art.

To be more precise, a first object of the present invention is to produce a tall plant cutting head to be associated with a self-propelled chipping machine that is also suitable for cutting tall plants having a diameter in excess of 7-10 cm,

such as poplar trees on a short two-year cycle.

Another object of the present invention is to produce a cutting head of more straightforward design than the equivalent heads carried out according to the known state of the art. Another object of the present invention is to produce a cutting head that requires less maintenance than the known types of heads. A further, not necessarily last object of the invention is to produce a cutting head that is less expensive than the heads resulting from the known state of the art and that does not entail the need to make any substantial additions or changes to the self-propelled chipping machine.

The aforementioned objects are achieved by a plant cutting head to be associated with self-propelled chipping machines of the type comprising a frame, complete with means for coupling it to said self-propelled chipping machine, with an associated unit for cutting said plants that, in accordance with the contents of the main claim, is characterized in that it comprises a conveyor unit situated downstream of said cutting unit, that has two or more rotating elements cooperating with one another so as to arrange the tree stems in a substantially horizontal position and carry them towards a chipping unit forming part of said chipping machine. According to the invention, the component parts of the cutting head are driven by mechanical transmission means.

To be more precise, the cutting head that is the subject of the invention has a first transmission system for driving the cutting unit and a second transmission system for driving the conveyor unit. The latter unit consists of three revolving rollers with a plurality of conveyor blades arranged around their perimeter.

The presence of the conveyor unit advantageously allows the cut poplar stems to be conveyed in the direction of the chipping unit of the self-propelled chipping machine at the right inclination so as to prevent them from sliding diagonally into the machine, thereby blocking the machine's operation.

To be more precise, the conveyor unit is composed of three revolving rollers placed so as to form a triangle, and each roller is equipped with a plurality of conveyor blades that bring the cut poplar trees into a position with their stems substantially horizontal. Another advantage lies in that, since the transmissions of the head of the

invention are of mechanical type, the head has a particularly straightforward design and requires little maintenance.

Another advantage lies, moreover, in that these mechanical transmissions simply need to be connected to the power supply of the self-propelled chipping machine in order to drive said transmissions without the need to add any hydraulic pumps or other costly elements.

The presence of two mechanical transmission systems for separately driving the conveyor unit and the cutting unit advantageously enables the mechanical power required to be drawn from different points of the self-propelled chipping machine, further simplifying the construction of the head that is the subject of the invention.

To be more specific, since the revolving elements of the conveyor unit turn at a lower speed than those of the cutting unit, the opportunity to connect them to two different points on the self-propelled chipping machine enables the units to be operated correctly with transmissions of limited size and complexity.

The aforesaid objects and advantages, and others that will be described below, will be highlighted in greater detail in the description of a preferred embodiment of the invention, provided here as a nonrestrictive example, with reference to the attached drawings, wherein: - Figure 1 shows an axonometric view of the cutting head of the invention;

- Figure 2 shows a cross-section of the cutting head of the invention; Figures 3 to 5 show several details of the cutting head of the invention;

- Figure 6 shows a further axonometric view of the cutting head of the invention; - Figure 7 shows the cutting head of the invention during an operating stage. The cutting head that is the subject of the invention is illustrated in Figure 1 , where it is indicated as a whole by the numeral 1 and shown associated with a self-propelled chipping machine T. The head 1 is of the type comprising a frame 2, complete with means 3 for coupling it to the self-propelled chipping machine T, with an associated unit 4 for cutting the plants close to the ground.

According to the invention, the cutting head 1 comprises a conveyor unit 5 that, as also shown in Figure 2, has three revolving elements 5a, 5b, 5c cooperating with one another so as to bring the cut stems into a substantially horizontal position and convey them towards a chipping unit 6 forming part of the

self-propelled chipping machine T.

The revolving elements 5a, 5b, 5c are consequently installed downstream of the cutting unit 4 and upstream of the chipping unit 6.

According to the preferred embodiment of the invention described herein, each of the revolving elements 5a, 5b, 5c, as also shown in the detail in Figure 3, is a roller 7 with a plurality of conveyor blades 8 around its perimeter.

The three revolving elements 5a, 5b, 5c are arranged, as shown in Figure 2, so that the three centers 10, 11 and 12 of the circumferences identified by the cross-sections of each of the rollers form the vertices of a triangle that, according to the preferred embodiment described herein, is a scalene triangle, the base of which lies on the line Y pointing towards the surface of the ground on which the head 1 rests.

According to other embodiments of the invention not illustrated or described herein, the triangle may be an isosceles triangle or an equilateral triangle. As for the cutting unit 4, this comprises a pair of lifting units 15, as shown in

Figure 4, each of which has a plurality of lifting prongs 16 arranged along the radii of the circumference identified by the casing 17 of the lifting unit 15.

The cutting unit 4 also comprises a pair of revolving blades 18, each of which is mechanically associated with a corresponding lifting unit 15. To be more specific, each revolving blade 18 is situated underneath its respective lifting unit 15 and has its center of rotation coaxial to the center of the circumference identified by the casing 17 of the corresponding lifting unit 15.

The mechanical association between the revolving blades 18 and the lifting unit 15 enables the two to turn at different angular velocities.

It is emphasized that this embodiment is described merely as an example and shall not be intended as restrictive.

Different embodiments are consequently feasible wherein, for instance, the revolving blades and lifting units may be present in a number other than two, or the revolving blades may be arranged differently with respect to the corresponding lifting units.

As concerns the driving of the cutting unit 4 and of the conveyor unit 5, this is obtained by means of two different transmission systems.

To be more specific, a first transmission system 19 mechanically connects the power supply of the chipping machine T to the cutting unit 4, while a second

transmission system 20 mechanically connects the power supply of the chipping machine T to the conveyor unit 5.

The first transmission system 19 comprises a gear wheel assembly 21 connected to the aforementioned power supply by means of moving parts consisting of a pair of pulleys 22 connected together with belts 23.

The second transmission system 20, on the other hand, comprises a gear wheel assembly 24 connected to the power supply by means of moving parts consisting of a cardan joint 25.

Thus, as shown in Figure 6, the only components added to the chipping machine T in order to operate the head 1 of the invention are advantageously the cardan joint 25 and the pulley 22.

Of course, this embodiment with two different transmission systems shall not be intended as restrictive and shall not exclude any other embodiments not illustrated or described herein, according to which there may be only one transmission system.

Finally, as shown in Figure 1 , the cutting head 1 of the invention comprises an extendable fork 26 for pressing against and guiding the fall of the cut stems.

In operational terms, the user associates the head 1 with the self-propelled chipping machine T using the coupling means 3 provided on the cutting head 1.

Then the user connects the pulley 22 and the cardan joint 25, which are installed on the chipping unit 6 of the self-propelled chipping machine T, to the head 1.

The driving force of the power supply serving the chipping machine T is thus mechanically transferred to the cutting unit 4 and to the conveyor unit 5 on the head 1 of the invention.

When the self-propelled chipping machine T is started, it drives the chipping unit 6, the conveyor unit 5 and the cutting unit 4.

As the self-propelled chipping machine T advances, as shown in Figure 7, the cutting unit 4 on the cutting head 1 cuts the plants P close to the ground, i.e. at a height of approximately 7-8 cm above the ground.

The cut plants are pushed towards the conveyor unit 5 by the lifting units 15 and, when the stem rests on the revolving elements 5a, 5b, 5c, the conveyor blades 8 draw the plant P into the conveyor unit 5 while keeping it in a position substantially horizontal to the ground.

The plants are thus advantageously fed most effectively into in the chipping unit 6 and are consequently prevented from blocking the machine. In the light of the above considerations, the cutting head of the invention achieves all the previously-stated objects. To be more precise, the object of producing a head for cutting tall plants that is even suitable for cutting stems with a diameter in excess of 7-10 cm, such as poplar trees on a short two-year cycle, has been achieved. The object of producing a cutting head of more straightforward design than the cutting heads carried out according to the known art has also been achieved. In fact, as explained in the above description, to drive the conveyor unit and the cutting unit, it comprises exclusively mechanical transmission systems that are well known to have a more straightforward design than hydraulic transmission systems. That is why the cutting head also achieves the object of requiring less maintenance than the known heads.

Finally, the invention achieves the object of producing a cutting head that is less expensive than the cutting heads carried out according to the known art because, as explained above, it only comprises mechanical elements that are driven mechanically, not hydraulically, so that its application to the self-propelled chipping machine only requires the addition of a cardan joint and a pulley, unlike the chipping heads of known type, which are hydraulically driven and consequently require the addition of hydraulic pumps. In the executive stages, the cutting head that is the subject of the invention may undergo changes that, though not illustrated or described herein, shall nonetheless be covered by the present patent, provided that they come within the scope of the claims that follow.

Where technical features mentioned in any claim are followed by reference signs, those reference sings have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.